Jun.2 (GMM) It is not clear if Ferrari and Honda will deploy their performance-upgraded engines this weekend in Canada.

The FIA this week has informed all the teams that the aforementioned two engine manufacturers have spent the first in-season 'tokens' of 2015 to up the speed of the respective power units.

In the rear of the two works Mercedes in Canada, meanwhile, will be fresh turbo V6s, but the German giant is yet to use any of its upgrade 'tokens'.

Auto Motor und Sport reports that the changes have all been made under the 'reliability' banner, meaning Mercedes still has 7 tokens up its sleeve.

"We suspect our competitors may also bring new power units" to Canada, technical boss Paddy Lowe said on Tuesday, "which this year may be upgraded in-season using development tokens.

"So it will be interesting to see whether and how the 'balance of power' is shifted this weekend," he added.

Indeed, just because Ferrari and Honda have handed in some 'tokens', doesn't mean they have to install those upgraded engines in Montreal.

Ferrari boss Maurizio Arrivabene had said in Monaco: "In Canada we will not use the tokens, but do not ask me when (we will) because I don't want the Germans (Mercedes) to know!"

Honda, however, appears much more likely to fit its token-upgraded power units to the McLaren cars in Canada.

Auto Motor und Sport correspondent Tobias Gruner on Tuesday said a Honda official had left Monaco promising more power for the long straights in Canada, Austria and Silverstone.

Gruner added: "Renault has not yet commented on its plans for Montreal, but as the Red Bull and Toro Rosso drivers have used 4 engines, the installation of new parts would automatically attract penalties."